Raw color grey fabric without dyeing and finishing, except for a small amount of direct supply market, most of them are supplied to the dyeing and finishing mill for further processing of bleach, color fabric and fabric for customer use. The original fabric contain a large number of impurities, including cotton, hemp fiber, synthetic fiber, oil, dirty and so on , they make the fabric handfeel rough, the color is not white, and the water absorption is poor. In order to follow up the process, the raw material need to be pretreated ,including pure physical processing and chemical processing.
Physical processing: in order to remove the wool from the surface of the fabric and the dimension stabilization for the purpose of heat shaping processing for cotton / polyester and linen/polyester . Chemical processing:it is used to process the embryo cloth with chemical agents and auxiliaries under certain processing conditions, including desizing, cooking, bleaching and mercerizing.
In pretreatment ,surface active agents such as osmosis and wetting agent should be added to the desizing and boiling stage, due to the presence of surfactants and mechanical motion, foam is produced.
Foaming material: Osmotic agent and wetting agent , the specific species are anionic surfactants , as a cooking agent and osmotic agent, sulfuric sulfonate sodium, lauryl benzene sulfonate, sodium lauryl sulfate, sodium alkyl naphthalene sulfonate and sulfuric acid of butyl sulfonate; Nonionic surfactants as wetting agents and osmotic agents have nonylphenol or octylphenol polyoxyethylene ether, as well as short fatty alcohol polyoxyethylene ether; Detergent (209 detergent or plain plus O)
Foaming characteristics : Mainly for surfactant foaming, at the same time the bubbling environment temperature is higher (60-90 degree), while the foaming environment is a strong alkaline environment, the alkalinity of the desizing is weaker than the cooking process.